Modification of the Benzene Moiety in the Quinolone Nucleus of 4-Hydroxy-6,7-Dimethoxy-2-Oxo-N-(Pyridin-3-Ylmethyl)-1,2-Dihydroquinoline-3-Carboxamide as an Attempt to Enhance its Analgesic Activity

A series of close analogs of 4-hydroxy-6,7-dimethoxy-2-oxo-N-(pyridin-3-ylmethyl)-1,2-dihydroquinoline-3-carboxamide modified in the benzene moiety of the quinolone nucleus were synthesized to identify the structural fragments determining their analgesic effect. Results of pharmacological tests found that these chemical changes had a relatively weak influence on the analgesic activity of the tested compounds, leading to the conclusion that the modified fragment interacted insignificantly with the biological targets.